It has become the practice to use child resistant closures for containers that have medicine or other products which might be harmful to small children. One problem with these closures is that they are hard to open by adults that have arthritis or are unable to grip a closure with sufficient strength to effect opening of the container by using two hands, particularly where one hand is unable to grip the closure with the required strength.
The CR closure of the invention can be opened by adults via the usual "push down and turn to open" by handling the closure manually with one hand.
One example of the usual "palm and turn" closure is disclosed in U.S. Pat. No. 3,857,505, issued 12/3/74. This patent shows the plastic overcap with the interengaging lugs that are actuated by pressing down on the overcap until the lugs engage so that rotation of the overcap will result in unthreading of the underneath closure.
Child resistant closures were created to reduce the accidental ingestion of dangerous substances by small children. The objective was to provide a closure system too difficult to open by small children but easy to open by adults.
Although the closure industry has been successful meeting the first objective, it is well known that child resistant closures are a constant source of irritation for adults who have great difficulties opening these CR closures. It is also well known that many senior citizens, and persons with arthritis, cannot physically open a CR closure. As a result, the containers are left open or the CR closure is replaced by a standard closure which defeats the very purpose of a CR closure. All CR closures require at least two consecutive or synchronized operations to open a CR package. For example:
1. A CR snap cap requires the rotation of the cap to align two arrows and then lift the cap;
2. A "squeeze and turn" closure requires the operator to squeeze the skirt of the closure at two specific locations and rotate the closure;
3. A "screw-loc" closure requires the operator to push down and rotate; and
4. Most two-piece CR closures require the operator to push down and rotate or pull up and rotate.
It should be noted that in all cases the closure, which is usually the smallest part of the package, must be handled by the hand or the fingers (rotated or squeezed) which may be physically too difficult for some adults, most senior citizens, and nearly all handicapped persons.
In addition to the child resistant closure exemplified in the above referenced U.S. Pat. Nos. 3,857,505, 4,469,235, issued Sept. 4, 1984, discloses the concept of a regular threaded closure having upstanding tabs on the top to give persons with an arthritic condition a means to increase the torque applied to the closure without positively gripping the skirt of the closure. This closure, however, is not a "press and twist" child resistant closure.